1. Technical Field
The present invention relates to an ultrasonic sensor unit.
2. Related Art
Ultrasonic sensors are used to measure distance to a target object, measure flow rates, perform nondestructive testing of ducts, and to conduct numerous other types of measurement or detection. A diaphragm-type ultrasonic sensor is known as a conventional example of such an ultrasonic sensor. In this type of ultrasonic sensor, a PZT ceramic thin film layer flanked by two electrodes is formed on one side of a diaphragm, and the electrical signals outputted from the electrodes are used to detect ultrasonic waves (see Japanese Laid-Open Patent Publication No. 2005-49301, for example).
An ultrasonic sensor array in which numerous ultrasonic sensors are arranged in an array by a MEMS technique can generate ultrasonic waves having sharp directionality in a desired direction. Techniques of three-dimensional scanning using an ultrasonic sensor array are therefore being researched.